3Com Switch 7750 Configuration Guide Guide

574 CHAPTER 54: DHCP SERVER CONFIGURATION
Network requirements
The DHCP server assigns IP addresses dynamically to the DHCP clients on the same
network segment. The network segment 10.1.1.0/24, to which the IP addresses of
the address pool belong, is divided into two sub-network segment: 10.1.1.0/25
and 10.1.1.128/25. The switch operating as the DHCP server hosts two VLANs,
whose interface IP addresses are 10.1.1.1/25 and 10.1.1.129/25 respectively.
The DHCP settings of the 10.1.1.0/25 network segment are as follows:
■ Lease time: 10 days plus 12 hours
■ Domain name: aabbcc.com
■ DNS server: 10.1.1.2
■ WINS server: none
■ Gateway: 10.1.1.126
The DHCP settings of the 10.1.1.128/25 network segment are as follows:
■ Lease time: 5 days
■ Domain name: aabbcc.com
■ DNS server: 10.1.1.2
■ WINS server: 10.1.1.4
■ Gateway: 10.1.1.254
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If you use the inheriting relation of parent and child address pools, make sure that
the number of the assigned IP addresses does not exceed the number of the IP
addresses in the child address pool; otherwise extra IP addresses will be obtained
from the parent address pool. The attributes (for example, gateway) also are based
on the configuration of the parent address pool.
For example, in the network to which VLAN interface 1 is connected, if multiple
clients apply for IP addresses, the child address pool 10.1.1.0/25 assigns IP
addresses first. When the IP addresses in the child address pool have been
assigned, if other clients need IP addresses, the IP addresses will be assigned from
the parent address pool 10.1.1.0/24 and the attributes will be based on the
configuration of the parent address pool.
For this example, the number of clients applying for IP addresses from VLAN
interface 1 is recommended to be less than or equal to 122 and the number of
clients applying for IP addresses from VLAN interface 2 is recommended to be less
than or equal to 124.